Hi Scott, Thanks for the info. It's my understanding that Simrad (Robertson) only manufactures the electronics and packages them with hydraulics from Hynautic. Sorry for the confusion about the pump; that's the same pump I have on the Westsail, but it is electric. She has a big and unbalanced barn door rudder. The pump on Seahorse is driven off the Lugger (port side) via a Twin Disc PTO. The steering system consists of a Wagner T4 ram with an A2 helm pump and a T4/Mannesmann flow control valve. It is indeed a robust system, but with a 7' draft, it has to be! John "Seahorse" Scott Strickland wrote: All I can tell is that I have dual Simrad RPU 300's. I do not know if they are Hynautic. I do not understand, does your sail boat autopilot run of your engine PTO? I have only heard of PTO autopilots being used when large rudder forces are encountered, generally over 75 feet.